![]() “What we often seem to forget about is the flip side of aging: the key mechanisms that slow down the deterioration.” Getting workers to lay eggs ![]() “When we talk about the mechanisms of aging, we usually only talk about the way things deteriorate,” says evolutionary biologist Thomas Flatt of the University of Fribourg in Switzerland, who has worked mainly with fruit flies and is co-author of an article about insect aging in the Annual Review of Entomology. Instead, it can be adapted to some extent as part of an evolved strategy to invest resources in the best possible way - on reproduction when they are plentiful, and on maintenance when they’re not. This fruit fly work suggests that the rate of aging is not set in stone. ![]() Some scientists have also shown that the lifespans of flies can be prolonged when some of the key genes involved in this nutrient-sensing network are inactivated. When food is scarce, this network will transmit signals that delay reproduction while increasing the animal’s longevity and investment in processes such as tissue repair - perhaps enabling the individual to wait for better days to come. Researchers have also shown that an entire network of genes involved in sensing the presence of nutrients such as amino acids and carbohydrates is responsible for this effect. Studies have found, for example, that when the fruit fly Drosophila melanogaster is fed a restricted diet, it can significantly extend its lifespan, but will produce fewer eggs. ![]() Some species, it turns out, can tilt their investment in body maintenance and reproduction one way or the other, depending on circumstances. In other words, many scientists reason, there must have been strong selective pressure to keep the queen alive for as long as possible by evolving delayed aging.īut how might that be achieved? Other insects offer some possible leads. OLEG KORZH / 500px/500Px Plus/Getty ImagesĪnd since the queen is the only one in a colony laying eggs, colonies with long-lived queens are likely to grow larger and send forth more young queens to start new nests, as well as males to fertilize them. Workers and queens seem to have different lifespans. By keeping the queen safe and providing her with the plentiful resources she needs to produce eggs for years on end, each worker helps in the spread of its own genes. This close genetic relatedness is why it makes sense that workers dedicate their lives to caring for the queen and her offspring, maintaining and protecting the colony’s nest, and foraging for food. All workers are daughters of the queen and, in many cases, any of those daughters could have grown up to become queens themselves had they received the appropriate royal treatment when they were larvae. Fruit flies offer aging cluesĭifferences in the genetic code can’t explain the unusual longevity of queens compared to workers. Apparently, these species have found a route that allows at least some of their kind to escape the constraints that force other animals to choose between longevity and lots of offspring.Ī few years ago, an international team of biologists set out to study how the creatures pull it off - and though there’s a lot still to learn, the first results of the project are starting to offer up clues. In many colonies, queens that lay hundreds of eggs every day can stay alive for years or even decades, while workers that never lay a single egg in their life will stop living after a few months. Yet in social insects such as termites, ants, bees, and wasps, the queens appear to have found a way to have their cake and eat it. So the more energy and nutrients an individual invests in producing offspring, the faster it will probably age, and the shorter its life will be. This contrasting pattern is so common it suggests that because reproduction and maintenance are both costly, animals simply can’t maximize both. In contrast, animals like elephants and humans raise only a few offspring and have bodies that survive for decades: If your size or lifestyle offers protection, you can afford to take your time. This is certainly true for insects, which, with some famous exceptions like cicadas, often have a life expectancy best expressed in days, weeks, or months. Since they’re always at risk of becoming another critter’s quick snack, the best way to ensure that their genes will make it into the next generation is having a bunch of young as soon as possible. Small animals don’t usually grow very old.
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